Thanks @evansd2 for beta testing and for sharing some ideas privately! I’d like to share some insights and some of my design thinking and process for this model. I figure some of this might help someone hoping to build models like this.
Background
This model was not my first Fusion360 model, but it is among the first 10 things I’ve done in Fusion. This is the most obvious revelation, but for me seeing my idea in 3D radically changed how I think about how everything around me is constructed. CAD really opened my mind up to the vast scope of spacial design that was previously out of reach.
So now I’m going around in the world wondering how I would build everything with a laser cutter. I now see forms that I know I can build and some that I can’t, and my mind starts to search for something that only appears like it can’t be done with a laser cutter. At that time I stumbled across JackCarter’s Tanks on Instructables and it blew my mind what he was doing. He was going so far beyond what I wanted to that I actually thought that my goal wasn’t so crazy anymore, I just needed a form. I honestly don’t remember how the F117 came to me but I remember the feeling I got when I decided to build it - pure raw anticipation and excitement.
I set off on the model and it took me over 3 days - I’d guess about 8 - 10 hours spent in design. As a new Fusion user - I probably made every mistake in the book but I did a lot right too and it came together! I couldn’t really believe it when the model was done and I really didn’t believe it when the first print came out. The scale was fantastic - large but not huge, and the overall shape was really spot on. I really liked how it turned out but there were lots of problems - the fingers were hammer tight, assembling was hard without labeling because many supports were easy to confuse, the tail supports were ugly and fragile, and there were build order challenges. A second pass and some tweaks made V2 much more pleasant and the improved tail just looked a lot better to me. I added labels to help with construction and set my wife to work building it with minimal directions to see what would happen. She got it done and the feedback from that build made it into the version that I posted here. Two coats of matte black paint and her build become the model that you see in the previous pictures I’ve posted.
MK1 - ProofGrade Draftboard
MK2 - mid construction - cheap birch ply
I showed the prototypes to some family and friends and got a lot of positive feedback. Most people don’t know what they’re looking at but still appreciated the craftsmanship.
Design Thinking
I set out with a design intent- this was going to be a tradeoff between a pretty desktop model and a heavy-duty tactile toy. I didn’t make up my mind then but knowing that there was a dichotomy between these two intents was helpful for making decisions as I went along. I kept coming back to this balance and in retrospect in nearly every piece I started with the strong-toy intent and made concessions towards the just-for-looks model. This ended up making for a pretty strange construction. You’ll see parts like O and F that are minimally attached with little regard for strength and parts like D that are hilariously overbuilt. I didn’t quite strike the balance that I wanted and ended up with a frankenstein. The worst one is the tail- which I opted to go for pure looks and stability be damned. Sorry :[ It all does come together nicely, and I did achieve a separate goal of being a glue-free construction. I just personally hate gluing up and I’m ok with the finger joint look so I always try to build stuff that you can assemble securely with just your hands.
The modeling process I took went something like this.
- Started with photos. I found profile views of the F117 from all sides. In Fusion, these became canvases which were projected on the 3 axis planes. I scaled these to about 25cm nose-to-butt as that just felt like a good size. Turned out that was a good call as even a little bit smaller would have likely resulted in a more compromised geometry. I knew I couldn’t perfectly match the F117 geometry but I wanted to get close.
- Drew the baseplate and started to project planes for each of the panels at the front. I only needed to do one side and used mirror as I went along. With a few panels in, as I went I could leverage points and axis from them to construct new planes for new panels. One by one I drew in the panels, extruded to the 3mm thickness and enclosed the form of the body. There was some creative interpretation of the actual form to what I could do. I knew that I could cover this thing in panels and maybe get every angle perfect, but instead I tried to keep it close enough that if you glanced quickly its hard to see what’s wrong. Any true F117 fan will see the quirks and the compromises and hopefully forgive me for them
Getting the panels right was so critical to getting the profile and look of the craft right. So I didn’t rush this part and had to redraw several panels. - The supports naturally come after the panels were in place. Again I used a lot of construction planes to locate an axis which is perpendicular to both the panel and the wing. Because each panel sits at a distinct angle to the wing each one required it’s own support. And since I’m thinking about the strong-toy intent each panel needed minimum two supports and as many finger joints as I could fit. This took a lot of time but seemed less daunting than the panels since I wasn’t designing I was engineering. Some supports were removed after printing a prototype and I took a final “what can I remove?” pass over the whole model.
- The tail was last and had an additional challenge in that the support needed to pass through a separate unrelated panel. By now this was actually a fun problem to solve. First try I stuck a support that mounted on the outside of the rear panel. Ugly AF and not very sturdy either so I scrapped it and determined that even the tail support needed to mount to the wing plate. That would tidy everything up and lend more strength to the tail.
- Manufacture in F360 for me meant making a separate copy of the whole model and one-by-one each component was moved and aligned to the XY plane. The result was a layout of all the parts as they would be laser-cut. Fusion keeps the link between the orignial components so I can still edit the 3D model and the cut layout will update with my changes. Love this feature but I don’t love having to manually place all those components. Still looking for a way to automate this operation. I used Colorific for post processing and exporting to SVG. I set the kerf compensation to 0.0625mm as this usually ends up giving a very nice fit that holds but does not require hammering for ProofGrade stuff or plywood in the 3.1 - 3.2mm range.
- Labels and stroke colors were all done in Illustrator. I create my own lettering for scoring using a process that is fast and easy to automate in Illustrator. I’d be happy to share this sometime in a separate post. Scored lettering is 10X more attractive vs engrave IMO and 10X faster so it gets a big thumbs up.
Next?
Some things I put off, maybe for a future model were landing gear and/or a stand. Also I am contemplating building another separate scoring layer for exterior details. This would make it possible for builders to choose between the labels or the details during their print.
Happy to answer any questions about this build!